JPH06148243A - Method of measuring impedance of piezoelectric vibrating plate - Google Patents

Abstract

PURPOSE:To provide a measuring method of the impedance of a piezoelectric vibrating plate which enables correct and moreover, automatic measurement of the impedance characteristic without correctly positioning a vibrating node of the piezoelectric vibrating plate. CONSTITUTION:A flat piezoelectric vibrating plate 1 is formed of a piezoelectric ceramic plate 2 having electrodes formed at front and rear faces thereof, and a metallic plate 3 bonded facing to the rear electrode of the ceramic plate 2. After the piezoelectric vibrating plate 1 is set along a direction of the plane, the characteristic of the impedance of the piezoelectric vibrating plate 1 is measured under the spreading vibration mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring impedance of a piezoelectric diaphragm.

[0002]

2. Description of the Related Art As shown in FIG. 2, a piezoelectric vibrating plate 1 used by being incorporated in a piezoelectric buzzer or the like includes a piezoelectric ceramic plate 2 having electrodes (not shown) formed on the front and back surfaces thereof, respectively. In general, the metal plate 3 having a large outer diameter is face-to-face joined to form a flat plate, and the impedance characteristic of the piezoelectric vibration plate 1 before being assembled is measured under bending vibration mode conditions. Measurements are being made. In this impedance measurement, a pair of right and left claw jigs 4 arranged to face each other is used to sandwich and support the vibration node points (nodes of the vibration mode) of the piezoelectric diaphragm 1 to be measured. Each of the claw jigs 4 is connected to an impedance measuring instrument 5 having a required function.

[0003]

By the way, in the impedance measuring method performed under the bending vibration mode condition, if the vibration node points of the piezoelectric diaphragm 1 are not accurately sandwiched by the claw jig 4, the original impedance characteristic is obtained. Cannot be measured, and if the sandwiched position is slightly different, the measured value may change greatly, which makes it difficult to detect the correct impedance characteristic. Further, since it is necessary to suspend and support the piezoelectric vibration plate 1, it is actually difficult to automate the measurement work.

The present invention was devised in view of these inconveniences, and the impedance characteristics can be accurately measured without accurately positioning the vibration node points in the piezoelectric diaphragm, and the measurement work can be performed. It is intended to provide an impedance measuring method that can be automated.

[0005]

In order to achieve such an object, a method of measuring impedance of a piezoelectric vibrating plate according to the present invention includes a piezoelectric ceramic plate having electrodes formed on the front and back surfaces thereof, and an electrode on the back surface side thereof. It is characterized in that a flat plate-shaped piezoelectric vibrating plate consisting of a metal plate face-to-face bonded to is placed along the plane direction, and then the impedance characteristic of this piezoelectric vibrating plate is measured under the spreading vibration mode condition. .

[0006]

According to the above method, the impedance characteristic of the piezoelectric vibration plate placed along the plane direction is measured under the spread vibration mode condition. In addition, it is not necessary to accurately position the vibration node points of the piezoelectric diaphragm and suspend and support them.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing a concrete configuration for carrying out the impedance measuring method according to the present invention.
According to the method of the present invention, a flat plate-shaped piezoelectric vibrating plate 1 used by being incorporated in a piezoelectric buzzer or the like, that is, a piezoelectric ceramic plate 2 having electrodes (not shown) formed on the front and back surfaces respectively.
And a metal plate 3 having a larger outer diameter than this and a metal plate 3 face-to-face bonded with a back side electrode of the piezoelectric ceramic plate 2 using a conductive adhesive (not shown) or the like. The impedance characteristic of 1 is measured under the spread vibration mode condition. In FIG. 1, parts and portions which are the same as or correspond to those in FIG. 2 showing a conventional example are designated by the same reference numerals.

That is, the piezoelectric vibrating plate 1 to be measured
As shown in FIG. 1, the metal plate 3 is placed on the measuring table 10 in a posture along the plane direction with the metal plate 3 on the lower side. It is in face-to-face contact with the lower electrode 11 arranged on the surface. In addition, on the piezoelectric vibrating plate 1 placed on the measurement base plate 10, that is, on the surface side electrodes of the piezoelectric ceramic plate 2 constituting the piezoelectric vibrating plate 1, the upper electrode plate 12 is interposed and the weight 13 is provided. Is placed, and the plurality of electrode rods 14 provided so as to project downward from the upper electrode plate 12 are pressed and brought into contact with each other at predetermined positions on the surface side electrode of the piezoelectric ceramic plate 2. Then, at this time, each of the lower electrode 11 and the electrode rod 14 is connected via a lead wire 15 to an impedance measuring instrument 5 having a required function similar to the conventional example. Therefore, the impedance characteristic of the piezoelectric diaphragm 1 is measured under the spreading vibration mode condition.

[0009]

As described above, according to the method of the present invention, the impedance characteristic of the piezoelectric vibration plate placed along the plane direction is measured under the spread vibration mode condition. It is not necessary to accurately position the vibration node points, and the impedance characteristic can be correctly measured without accurately positioning the vibration node points. Further, unlike the conventional example, it is not necessary to suspend and support the piezoelectric diaphragm, and it is sufficient to simply place the piezoelectric diaphragm along the plane direction.
There is also an effect that the impedance measurement work can be automated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a specific configuration of an impedance measuring method according to the present embodiment.

FIG. 2 is an explanatory diagram showing a specific configuration of an impedance measuring method according to a conventional example.

[Explanation of symbols]

 1 Piezoelectric vibration plate 2 Piezoelectric ceramic plate 3 Metal plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshiaki Yamashita Toshiaki Yamashita 2 26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Masataka Kida 2 26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing

Claims (1)

[Claims] 1. A flat plate-shaped piezoelectric vibrating plate (1) comprising a piezoelectric ceramic plate (2) having electrodes formed on the front and back surfaces, and a metal plate (3) face-to-face bonded to the back surface side electrodes. A method for measuring the impedance of a piezoelectric diaphragm, which comprises placing the piezoelectric diaphragm (1) in a plane direction and then measuring the impedance characteristic of the piezoelectric diaphragm (1) under a spread vibration mode condition.